Effect of various carbon nanofillers and different filler aspect ratios on the thermal conductivity of epoxy matrix nanocomposites

Abstract

The effectiveness of carbon nanofillers in improving the thermal conductivity of polymer matrix composites has been extensively studied. However, the mechanisms that lead to the effective reinforcement of composite thermal conductivity at the nanoscale remain unclear, and the significant role of filler aspect ratio in determining composite thermal properties needs to be further clarified for various carbon nanofillers. The primary focus of this study was on understanding how important this factor is in determining the thermal properties of polymer matrix composites. The effect of various carbon nanofillers on the thermal conductivity of epoxy matrix composites was studied with special emphasis on the relationship between filler aspect ratio and composite thermal properties. The effect of filler loading on composite thermal conductivity was investigated, and the role of temperature in thermal conductivity improvement was also evaluated. The results indicated that the aspect ratio of carbon nanofillers is of great significance for improving their reinforcing effect on the thermal performance of polymer matrix composite materials. Graphene in any form can improve composite thermal conductivity more effectively than carbon nanotubes and conventional carbon-based nanofillers. A seven-fold increase in composite thermal conductivity has been achieved by incorporating 6% graphene oxide by weight into the polymer matrix. The resultant polymer nanocomposites may be more attractive at elevated temperatures for applications in thermal management, if their thermal stability problems can be effectively addressed.